We evaluated trends in the use of echocardiography among residents of Olmsted County, Minnesota, from January 1, 1975, through June 30, 1987. Annual examinations per 100,000 population among Olmsted County residents increased 6-fold from 264 in 1975 to 1,644 in 1986. Given the pattern of echo use in Olmsted County, these population-based data project a potential annual utilization of 4 million echo exams in the United States. Marked increases over time in labeling of patients with regurgitant valvular heart disease were noted following the introduction of Doppler echocardiography. The diagnostic labeling associated with this evolving technology and the resultant apparent epidemic of valvular regurgitation present a significant clinical technology assessment dilemma.